[hale1776]

Y is correct I used wrong term
the 94's use vacuum actuated power valve that needs to be blocked/changed to keep it from opening too soon. It's not rocket science, but it can be a pain in the ass to get set up so the setup works right. 97's have a mechanically actuated PV that opens when the accelerator pump plunger reaches the bottom of the bore. No guesswork about when the PV opens! Otherwise, they're both just 2bbl carbs...